Patent GB-374356-A (GB)
Title: Improvements in or relating to processes and apparatus for the production of artificial filaments, films and similar products
IPC: D01D1/06
Filed: 1931-10-21
Abstract: 374,356. Artificial threads, films, &c. BRITISH CELANESE, Ltd., 22, Hanover Square, London. Oct. 21, 1931, No. 29211. Convention date, Oct. 29, 1930. [Class 2 (ii).] A pigment for lustremodification or colouration is introduced into a solution of a cellulose derivative in an organic solvent during its direct passage from the main filters to the spinning jets and after it has been divided between two or more pipe lines ; preferably the point of introduction is close to the spinning jets. By this means the character of the product can be changed without it being necessary to clean out a large portion of the plant at each alteration, and small quantities of particular products are readily obtained. A variation of the properties of the product along its length can be produced by varying the proportions of pigment and spinning solution regularly or irregularly. In the dryspinning plant shown, a pigment mixture from a tank 9 and spinning solution from a pipe 14 are fed by intergeared pumps 11, 13 into a mixer 15, the mixture being forced by a pump 16 into a header 7, and thence by pumps 8 to the individual jets of a single set of spinning cells. A pressure release valve 17 and byepass 18 allow any excess of solution delivered by the pump 16 to be returned. The pigment may be added in the form of a concentrated suspension, obtained by grinding in a ball or colloid mill with water, oil, part of the spinning solution, or the solvent used in the spinning solution ; dispersing agents and protective colloids may be added. The particles of the pigment preferably have a diameter between 0.1 and 5 microns, and the amount of pigment may be from 0À1 to 10 per cent of the base of the yarn. Pigments suitable for modifying the lustre and opacity are: tin oxide or phosphate, antimony oxide, titanium dioxide, barium sulphate, lead sulphate, calcium sulphate, zinc oxide or carbonate, alumina, silica, barium or calcium borate, silicates such as clay, talc, mica, diacetyl or dibenzoyl benzidine, diacetyl tolidine, dinaphthyl urea, anthraquinone, anthracene, or natural or synthetic resins. Suitable coloured pigments are ochre, sienna, chrome yellow, tin bronze, Venetian red, red lead, vermilion, ultramarine, Prussian blue, Milori blue, Guignet's green, verdigris, chrome green, raw or burnt umber, Vandyke brown, finely-divided metals, lampblack, graphite, or a mixture. The cellulose derivative may be an ether or organic ester. In an example, a solution contains 1 part of acetate to 3 of acetone. The products may be filaments, yarns, ribbons, films, bristles, artificial horsehair or straw, or the like. According to the Specification as open to inspection under Sect. 91 (3) (a) instead of pigments there may be introduced dyestuffs, diluents such as water, alcohols, or hydrocarbons, medium or high boiling solvents, plasticizers, volatile liquids or gas-evolving salts to produce hollow filaments, or solutions of salts which form insoluble compounds with other salts in a coagulating bath ; also products of non-uniform plasticity may be stretched, in which case a solution of the base itself may form the modifying agent. This subjectmatter does not appear in the Specification as accepted.